The present invention relates to a color liquid crystal display. More particularly, the present invention relates to a raw panel used in a color liquid crystal display that comprises all R,G,B cholesteric liquid crystal materials, and to a method for manufacturing a liquid crystal display using the raw panel.
A cholesteric liquid crystal display is a display device comprising chiral nematic liquid crystal materials which are bistable in absence of a field. The two bistable textures are the weakly-scattering focal conic texture and the reflective planar texture in which selective light having a wavelength corresponding to the helical pitch of liquid materials are reflected. The pitch length can be controlled by adjusting the amount of chiral dopants.
For example, a cholesteric liquid crystal display (hereinafter referred to as a cholesteric LCD) adopting liquid crystal material having a helical pitch length of 550 nm results in a single-color display that reflects green light for the display of images.
Hence, for full color images, a cholesteric LCD containing at least three different types of cholesteric liquid crystal materials corresponding to the wavelengths of at least red, green, and blue light are needed.
A full colored cholesteric LCD can be achieved by stacking each colored material layer in separate panels. The stacked color display requires at least four substrates to accommodate R,G,B colored materials, as well as addressing means to control three different panels simultaneously, which increases the cost of display devices.
Another way to produce a full color display is by injecting each colored liquid crystal material into separate regions within a single panel. This is referred to as a 1-panel cholesteric LCD. However, there is the practical difficulty of defining each individual microscopic pixel with different amounts of chiral dopants.
U.S. Pat. No. 5,825,451 discloses manufacturing methods of a 1-panel cholesteric LCD in which twist agents (chiral dopants) are deposited at predetermined points corresponding to each colored pixel on a first substrate, which is then assembled with a second substrate to define separate interstitial regions for each pixel, and liquid crystal materials having an initial pitch are introduced into the interstitial regions.
Twist agents can be deposited by a printing method, however, it is difficult to control the precise amount of twist agent required to reflect proper wavelengths. Thus, a color display device with good picture quality cannot be obtained.
According to the present invention a raw panel used for a liquid crystal display and a method for manufacturing 1-panel color liquid crystal display devices is provided in which different types of cholesteric liquid crystal materials are easily injected separately into a single liquid crystal panel without having to undergo an elaborate printing process of twist agents, thereby realizing a high resolution color display.
According to an embodiment of the present invention, a raw panel for a liquid crystal display is provided having a first substrate which includes first electrodes. A second substrate is provided opposing the first substrate. The second substrate includes second electrodes on a surface that opposes the first substrate. A plurality of main walls having a predetermined height is arranged in a striped pattern between the first and second substrates to thereby define a plurality of channels. The channels include sets of pixels, each set of pixels being formed by three neighboring channels. First sub-walls are mounted between the main walls defining first channels in sets, to thereby divide the first channels into at least two separate spaces. The first sub-walls are mounted at a predetermined first distance from a first end line, which is formed along one of two ends of the main walls. Second sub-walls are mounted between the main walls defining second channels in sets, to thereby divide the second channels into at least two separate spaces. The second sub-walls are mounted at a predetermined second distance from the first end line. The raw panel is opened between the main walls at the first end line as well as at a second end line which is formed along an end of the main walls opposite that along which the first end line is formed.
According to an embodiment of the present invention, the predetermined distance at which the first sub-walls are mounted from the first end line is different from the predetermined distance at which the second sub-walls are mounted from the first end line.
According to an embodiment of the present invention, a method for manufacturing a liquid crystal display is provided that includes preparing a raw panel. A first substrate includes first electrodes. A second substrate is provided opposing the first substrate. The second substrate includes second electrodes on a surface that opposes the first substrate. A plurality of main walls having a predetermined height are arranged in a striped pattern between the first and second substrates to thereby define a plurality of channels. The channels include sets of pixels, each set of pixels being formed by three neighboring channels. First sub-walls are mounted between the main walls defining first channels in sets to thereby divide the first channels into at least two separate spaces. The first sub-walls are mounted at a predetermined first distance from a first end line which is formed along one of two ends of the main walls. The second sub-walls are mounted between the main walls defining second channels in sets, to thereby divide the second channels into at least two separate spaces. The second sub-walls are mounted at a predetermined second distance from first end line. The raw panel is opened between the main walls at the first end line as well as at a second end line. The second end line is formed along an end of the main walls opposite that along which the first end line is formed providing sealing spaces between the main walls along the second end line. In the method, liquid crystals are injected into third channels, which are channels that do not have first and second sub-walls formed therein. The third channels are then sealed by closing off the spaces between the main walls defining the third channels. The raw panel is cut along a first cutting line, which is at a location such that the first sub-walls are removed after the cutting is performed. Liquid crystals are injected into the first channels. The first channels are sealed by closing off the spaces between the main walls defining first channels. The raw panel is cut along a second cutting line, which is at a location such that second sub-walls are removed after the cutting is performed. Liquid crystals are injected into the second channels and the second channels are sealed by closing off the spaces between the main walls defining the second channels.
According to an embodiment of the present invention, the liquid crystals are cholesteric liquid crystals.
According to an embodiment of the present invention, the sealing of the first, second, and third channels is performed using an ultraviolet ray hardener, namely a sealant hardened by ultraviolet rays.
According to an embodiment of the present invention, the first and second sub-walls are mounted substantially perpendicular to the main walls.
According to an embodiment of the present invention, the first and second cutting lines are substantially parallel to the first end line.
According to yet another embodiment of the present invention, a raw panel for a liquid crystal display is provided, including: a first substrate including first electrodes; a second substrate opposing the first substrate, the second substrate including second electrodes on a surface that opposes the first substrate; and a plurality of main walls having a predetermined height between the first and second substrates to thereby define a plurality of separate channels. The channels include sets of pixels, each set of pixels being formed by at least two neighboring channels, wherein at least one channel of the sets is divided into two separate spaces along a longitudinal direction of the main walls by a sub-wall mounted between the main walls.
According to another embodiment of the present invention, each set of pixels is formed by three neighboring channels.
According to another embodiment of the present invention, each set of pixels includes sub-walls mounted between the main walls defining each different channel, the distances of the sub-walls to a first end line, which is formed along one of two ends of main walls, being formed differently.